1. Field of the Invention
This invention relates to shaft seals and in particular to a unitized seal that is also grease-purgeable.
2. Description of the Prior Art
While unitized dual-lip seals are known (see, for example, U.S. Pat. No. 3,963,248 assigned to the same assignee as is the present application) and while grease-purgeable seals are also known in the art, there are no known seals that are both unitized and grease-purgeable. Previous unitized seals were not grease-purgeable, and previous nonunitized, grease-purgeable seals were difficult to properly install (see, for example, the prior art seal shown in FIG. 1 of this application).
It is an object of the present invention to overcome the problems in the prior art by providing a seal that is unitized, grease-purgeable, and easy to properly install.